Tangbagou Fm
Type Locality and Naming
The type section is located at Tangbagou, 14 km south of Dushan County Seat, Guizhou. It was named by Ding Wenjian in 1931.
Lithology and Thickness
Limestone. Dominated by gray to dark-gray moderately thick-bedded micritic limestone, clayey banded limestone, nodular limestone, clayey limestone, quartz sandstone, and black and brown shales. With intercalations of one or more layers of quartz sandstone at Dushan, Libo, Jiuqian of Sandu; with a clastic rock layer at Pingtang, Ganzhai, Huishui and Longli; lacking sandstone in some areas, containing minor chert nodules or bands, or intercalated with dolomite and dolomitic limestone. It is as thick as 300 m at Dushan, Libo, Pingtang and Huishui; but only tens of or several meters thick at Duyun and Sandu on the margins of the Jiangnan Oldland and Central Guizhou uplift, and the Longli, Guizhou and Changshun areas.
Relationships and Distribution
Lower contact
Conformable over the Gelaohe Fm [or locally, Qijing region, with Zaige Fm]
Upper contact
Disconformable under the basal sandstone of the Xiangbai Fm
Regional extent
GeoJSON
Fossils
Corals Pseudouralinia tangbakouensis, P. gigantea, etc.; Brachiopods Eochoristites chui, E. dushanensis, Martiniella chinglungensis, M. Pentagonia, M. asinuata, Yanguania dushanensis, Ptychomaletoechia kinglingensis, Cleiothyridina obmaxima, C. submabranacea, etc. The fossils are mainly enriched in the middle and upper parts of the formation.
Age
Depositional setting
It is interpreted as platform littoral-neritic deposits
Additional Information